Furnace port



YAug. 3, 1937. s. A. FczFeTER4 FURNACE PORT Filed Deo. 5, 1936 INVENTORnaci-3S.

Patented Aug. 3, `1937 lPATENT ,OFFICE FURNACE PGRT Samuel Forter,Bellevue, Pa., assignor to Forter-Teichmann Company, a corporation ofPennsylvania Application December 5, 1936, Serial No. 114,405

6 Claims.

My invention relates to regenerative furnaces, and more particularly tothe ports of such furdescribed as it has been applied to glass furnaces.The usual glass furnace includes one or more pairs of cooperating portsthat communicate with regenerators arranged in known way at oppositesides of the furnace. Air for sustaining combustion within the furnaceis heated by the checkerwork in one regenerator while the hot wastegases of the furnace are led through .and heat the checkerwork in theother regenerator. The heated air, together with liquid or gaseous fuel,is introduced to the furnace chamber through the port or ports at oneside of the furnace, and the waste gases find escape through the port orports at the opposite side. And from time to time the furnace isreversed, and ythe ports which had been serving as the firing portsbecome the outgo ports, andthe ports which had been serving as the outgoports become the flring ports. 'Ihe art is familiar with such practiceand further detail is needless.

Ports in large number and of various designs have been proposed angtried in practice, and it has been found that ports which operate withhigh efliciency as firing portsfail to function with desired efficiencyas outgo ports. \Aiter nately, ports which are particularly effective asoutgo ports fail to give highesteiiiciency as firing port's.

My object is to provide a portin which high eiliciency is obtained bothwhen the port serves as a firing port and when itserves as an outgoport. The invention consists in refinements in port construction and inmethod of operating a port to re a furnace. My port is of simple andeconomical construction, and is easily inspected and maintained inservice. The port is of such design that so far as may be the gasesflowing therethrough flow in stream-lines. When serving as a firingport, the lwalls of my structure are by a blanket of air protected fromthe burning fuel, and, when serving asjan outgo port, maximum capacityfor the conduction of waste gases is provided. Additionally, the port ofmy design minimizes and eliminates the usual tendency for dust andmolten particlesentrained in the waste gases streaming from the furnace,to settle and collect in the port and thereby interfere with normaloperation.

In the accompanying sheet of drawings, Fig. I is a View in axial andvertical section of a port embodying the invention, and Fig. Il is aview In exemplary way the invention will be of the port in crosssection, on the plane II--II of Fig. I.

In the drawing, the reference numeral I in-' dicates the roof, and 2 theside-wall of a fragmentarily illustrated glass furnace or tank F. 'I'henumeral 3 is applied to one of the regenerators -which in known way isorganized with the furnace F, and a port P, illustrative of theinvention, establishes communication immediately from the top of theregenerator to the chamber of the furnace. In well-known manner, thefurnace, the regenerator, and the port are constructed of refractorybricks and tiles, laid up with mortar and reinforced and tied withstructural steel and tie-rods.-

'Ihe port P includes a horizontally extending throat or passageway Ithat opens at its righthand end (Fig. I) intothe furnace chamber, and atits left-hand end opens into a passage Il extending upward from the topof the checkerwork embodies, as usual. in regenerator 3. Only the upperportion of the regenerator 3 and the top course of checker-blocks of'thecheckerwork 5 are shown in the drawing. The floor of the port P isconstructed of refractory slabs I2 that are readily replaceable inservice, and the roof of the port and upper end of passage II arecovered in common by a horizontally extending arch I3. And it is to benoted that the sidewallsl 9, VSi of theport (and the roof and oor I3,I2, respectively) extend in parallelism, whereby the throat I0 of theport is of substantially uniform cross-sectional area throughout itshorizontal extent.

When the port is' operating as a firing port, air ows upward through thehot checkerwork in the regenerator 3 and is heated. Under the influencesof buoyancy, and of draft produced by the usual furnace stack (notshown), the heated air sweeps into the horizontal throat IIJ of theport. Fuel is introduced tothe streaming air, and a mixed and burningcolumn of fuel and air is projected from the throat I0 into the furnaceF.

In accordance with my invention, the preheated air rising from the hotcheckerwork 5 is caused to flow in divided stream into the throat of theport, and to such end I provide in the port a ver- -tical partition I4,whose upper edge Ila lies slightly above the level of the floor (I2) ofthe port. The partition Il extends transversely be- I tween the sidewalls 9, 9 of the port and parallels the side-wall 2 of the furnace.Thus, the uptake i I is divided into two passages IIa and IIb; thestream of air flowing upward in passage IIb is greater than the streamin the passage IIa, and the larger of such vertical streams is moreremote from the furnace F.than the smaller. Into the smaller and lessremote stream of air 5 lsweeping upward through passage IIa, I introducefluid fuel. The fuel is natural gas in this case.

More particularly, a fuel injector or burner is arranged in the verticalwall of the port nearest l0 to the furnace, and such injector comprisesa rectangular manifold 4 installed in the vertical end-Wall 8 of theport. The manifold 4 is constructed of refractory material. Through therear-wall of the manifold a fuel-introducing pipe E extends, and in thefront-wall an elongate,

narrow, horizontal slot 1 opens. Advantageously, the heat-resistingmanifold 4 is embodied as a unit of masonry in the vertical end-wall 8of the port, and it will be perceived in Fig. II that the burnermanifold is centered in the vertical mid-plane of the port, with theopposite ends of the slot 1 spaced from the respective side-walls 9, 9of the port. The feed pipe 6 introduces the gaseous fuel into a chamberc within the burnerA manifold, and the fuel streams from such chamber(through slot 1) in the forrn of a thin sheet of gas.

lIt will be observed that the fuel enters the burner manifold at a pointadjacent to the floor chamber c, and leaves by way of slot v'l locatedadjacent to the top of such chamber. Upon entering the chamber c the gasexpands and its velocity falls; then, as it ows through slot 1, itsvelocity rises again. In service my fuel-injecting manifold or burnerhas proved very efflcient. 'Iurbulence of flow in the injected fuel isminimizedthe flow of fuel is stream-line as it is directed angularlyinto the ascending stream of preheated air in passage l la. Upon themerg- 40 ing of the fuel with the heated air in passage I Ia, combustionbegins, and it will be understood that the passage Il a comprises aprimary combustion chamber, while the hot air rising therein comprisesthe primary combustion air. In the drawing, I have employed short, darkarrows to indicate the flow of the fuel introduced to the port, andrelatively long arrows to indicate the movement of the preheated air. y

As may be visualized in Fig. I, the sheet of gaseous fuel injected intothe passage IIa is deflected upward and merges tangentially with thevertical stream of primary combustion air owing upward in passage Ila.Between the opposite ends of slot 1 and the respective side-walls of theport, vertically flowing side-currents of air `operate to screen theside-walls of the port and to prevent undue lateral spreading of theinjected sheet of fuel. (Note the arrows in Fig. II, the short arrowsindicating the fuel and the long ar- 6o rows the air.)

As has been already mentioned, the air flowing in passage IIa comprisesthe smaller com'- ponent of the double or divided stream flowing upwardfrom the checkerwork 5. The larger 55 component of the divided stream,rising through passage IIb, flows horizontally over thetop of partitionI4, across the top of passage IIa, and into the throat I0 of the port,with the consequence and effect that the merged and partially mixedstreams of fuel and air flowing vertically upward to the top of passageIIa are (by the horizontal stream of air) gradually bent orfolded into ahorizontal course of flow, as the arrows indicate in Fig. I. The airentering the throat Il from passage IIb forms a horizontal curtain ofair over the mixed stream of fuel and air ris'- ing from passage IIaandflowing over the floor I 2 of the port, and this enveloping curtainof air, and the side-currents of air mentioned above, protect the roofand side-Walls of the port from immediate contact with the burninggases. As the movement of the column of fuel and air progresses fromleft to right (Fig. I) in the throat I0', combustion-sustaining air isby the burning gases drawn from said enveloping curtain of air. Thus,the air flowing from the passage IIb and forming the air curtain in thethroat I0 provides secondary combustion air, and the throat Ill itselfmay be considered a secondary combustion chamber.

Contrary to usual practice, the mouth M of the port is not constricted,but is of the same cross-sectional area as the throat I0. The velocityof flow of the burning column of fuel and air projected into the furnaceF is produced solely by the buoyancy of the heated air rising into theport and the draft of the furnace, augmented by the effect of theexpansion of the gases, as combustion progresses from the point of fueladmission (slot 1) to the mouth M of the port. As already mentioned, theopposite walls of the port are parallel throughout; the cross section ofthe column of fuel and air within the throat I0 is held to uniform-valuethere is no choking of flow within the port, and turbulence isreduced to a minimum.

If desired, auxiliary streams of fuel may, by means of orifices I6, beprojected through the opposite side-walls of the port and into theburning column streaming through the throat I0.

From the foregoing description, it Will be understood that, intheoperation of the port P, preheated air is led upward in divided streamfrom the hot checkerwork of the regenerator 3; that one of thecomponents of such divided stream is larger than the other, and moreremote from the furnace'F into which the port opens; that a sheet offluid fuel is directed into the smaller component of the verticallystreaming air and causedto merge tangentially therewith; that the mergedstreams of fuel and air about to enter the throat ID are deflected froma vertical into a horizontal line of flow; that the air of the largercomponent of the vertically divided stream is caused to form a curtainover the deflected and horizontally flowing stream of fuel and air; andthat the cross-section ofthe gaseous column in throat I0 is held tosubstantially uniform value, as the gases progressively burn, expand,and advance with progressively increasing velocity toward and throughthe mouth of the port.

When the furnace is reversed and the port P becomes the outgo port, theunconstricted mouth and throat of my port offers minimum vresistance tothe flow of waste gases from the furnace to the regenerator 3. Withinthe port there are no shoulders or other protuberances, such as mighttend to obstruct the flow of the waste gases and to cause Aprecipitationof the particles of dust and molten material entrained therein, asusual. It

-will also be observed that the end-wall 8 of the port is recessed atI5, in such manner that the inner face of the burner "4 is offset fromthe inner face of said wall 8 and lies below the inner end I2a of thefloor of the port. Th'us, the body of the burner 4, and particularly thefuel-'injectiing slot 1 of the burner. lies out of the line of flow ofthe waste gases streaming through the port, whereby it is impossible fordust and slag included in the waste gases to accumulate upon the burnerand plug such slot 1.

Whereas in the foregoing specification the opening through which thefuel enters my port is shown as an elongate slot 1, it is contemplatedthat a plurality of orifices may be so arranged longitudinally of theburner manifold, i. e. transversely of the end-wall 8 of the portstructure, as to inject the fuel substantially in the form of a sheetthat merges tangentially with the primary combustion air.

It is to be understood that the principles of my invention may,advantageously, be embodied and employed in open-hearth furnaces, and inother sorts of furnaces in which it is desired to project a column offuel and air into a furnace chamber. I have spoken of the throat Il! ofthe port as a horizontally extending throat, and it is to be noted thatby such, expression I do not limit the invention to a throat or passage.

which literally is horizontal. On the contrary, I intend a passage whosegeneral extent is in horizontal direction, and include within the termsof the appended claims passages which are inclined to the horizontal, asthe usual throats of open-hearth furnace ports are inclined. And it ismanifest that the vertical passages lla and IIb leading into the throatof the port may be inclined to the vertical without departing from theessence of the invention. y

In this case the means for preheating combustion-sustaining air enteringthe port comprise a regenerator including a single body of checkerwork.It will be evident to those skilled in the art that two bodies ofcheckerwork may be embodied in the regenerator kand verticallypartitioned lfrom one another to operate in. the manner described, orthe two bodies of checkerwork may be arranged in companion regenerators.vertical passages is contemplated within the terms of certain of theappended claims. And it is to be understood that such obviousmodifications f as these do not avoid the spirit of the invention.

I claim as my invention:

1. A furnace port including vertically and horizontally extending wallsdefining a passageway for air streaming from air-preheating means into afurnace, and fuel injecting means opening through the verticallyextending walls of the port and off-set from the line of gaseous now insaid passageway, whereby, when the port is serving as an outgo port forthe waste gases of said furnace, said last means are protected from theusual solid and molten inclusions in said waste gases.

2. The method of ring a regenerative furnace. which method consists inleading air from hot checkerwork upward through two passages, one moreremote and one less remote from the furnace, directing fluid fuelangularly into the air owing upwardly in the less remote passage, and,by contact with the upwardly streaming air, deflectlng the flowing fuelinto an upward course of flow, directingthe air flowing upward in themore remote passage, inthe form of an air curtain, horizontally acrossthe open mouth of the less remote passage and transversely. of themerged streams of air and fuel flowing upward Indeed, theprovision ofmore than twotherefrom, and thereby bending and folding such mergedstreams of air and fuel under said horizontal air curtain and into ahorizontally extending column, and projecting such column, with themerged air and fuel streams ilrst mentioned lying beneath said aircurtain, into said furnace.

3. The method'of ring a regenerative furnace, which method consists inleading air from hot checkerwork upward through two passages, one moreremote and one less remote from the furnace, directing iluid fuelangularly into the air flowing upward in the less remote passage, and,by contact with the upwardly streaming air, deiiecting the flowing fuelinto a vertical course of flow, directing the air flowing upward in themore remote passage, in the form of an air curtain, horizontallyy across`the open mouth of the less remote passage and transversely of themerged streams of air and fuel flowing upward therefrom, and thereby'bending and folding such merged streams of air and fuel into ahorizontally extending column in which the stream of fuel includingquantities of primary combustion air lies lowermost, and projecting suchcolumn, with the merged air and fuel streams first mentioned lyingbeneath saidair curtain, into said furnace.

f 4. The method of firing a regenerative furnace, which method consistsin leading a fluid fuel and primary combustion air vertically through anupwardly open passage and into the throat of a horizontally extendingfiring port, preheating secondary combustion air and feeding it underthe influences of draft and buoyancy into said port and leading itacross the open mouth of said passage and transversely of said stream ofprimary air and fuel, and thereby bending and folding said ascendingstreams of primary air and fuel to provide in said port a relativelylong column of advancing gases in which a mixed and burning stream offuel and primary air is screened from above by a curtain of saidsecondary air, and, as the gases in the column progressively burn,expand and advance through the port and into the furnace withprogressively increasing velocity, maintaining the cross-section of saidelongate column at substantially uniform value.

5. A furnace port including a vertical passage for leading air upwardlyinto a horizontally extending passage, a fuel inlet opening through thewall of said vertical passage, the mouth of said inlet beinghorizontally offset outward from the eiectiveinner face of the wall ofsaid vertical passage,`whereby, when said port is serving as the outgoport for the waste gases of the furnace, the mouth of said inlet isshielded from the usual solid and molten particles included with suchgases.

6. A furnace port including a vertical passage for leading air upwardlyinto, a horizontally extending passage, a manifold embodied in the wallof said vertical passage, said manifold including a fuel-electingopening horizontally offset from the adjacent wall portions of saidvertical passage, whereby, when said port is serving as the outgo portfor the waste gases of the furnace, the mouth of said ope'ning isshielded from the usual solid and molten particles 'included with suchgases.

SAMUEL A.;FORTER.

